On board aircraft, fuel-cell configurations may be used for obtaining water from the fuel-cell exhaust air. For this purpose, it is necessary to condense out the water contained in the exhaust air flow using a condenser.
A cooling loop may be provided for condensing water vapor, to which two heat exchangers are coupled. These are a primary heat exchanger (PWT) and a secondary heat exchanger (SWT).
The condensation may be performed by indirect cooling using coolant, which is finally cooled by external air. This indirect cooling may be necessary to avoid icing of the primary heat exchanger by direct contact with external air, where the temperature may be significantly below the freezing point of water. However, this construction is complex and connected with a high overall system mass.